Archaeoacoustics reconstructs the sound of Stonehenge

English scientists have awoken the sounds of Stonehenge.

A team of scientists lead by Dr. Bruno Fazenda of the University of Salford in the UK has reconstructed the soundscape of the Stonehenge circle. Using the practice of archaeoacoustics and state-of-the-art sound equipment at both the original cultic circle in England's Salisbury Plains and the reconstruction in the US state of Washington, the scientists behind a new study have resurrected a part of the structure's sonic awe.

Because the original Stonehenge is incomplete, with some of the stones toppled, and because electric generators are not permitted, as well as the relative nearness of a main highway, the study's authors decided to augment the measurements they took there with measurements from the World War I memorial Stonehenge replica at Maryhill Museum.

Fazenda explained what they were looking for.

"For both sites, the goal was to obtain impulse responses at specific source-receiver locations. Measured impulse responses contain all the acoustic information from a system comprised of the enclosure, the position of the source and the position of the microphone. From the impulse response it is possible to derive frequency response functions, determine the decay rate of energy, and plot energy time curves (ETC) at the measured positions. These acoustic descriptors of the space are used as an attempt to describe the acoustical behaviour of the space in objective and comparable terms. The measurements are presented in the results section."

Because electricity is not allowed in the original henge, Fazenda and his crew popped balloons to capture those responses with a battery-operated field recorder. In such a situation, said Fazenda, "only the first few milliseconds of energy decay are available for measurement and a full length T60 reverberation time has to be extrapolated from this."

With electricity available at Maryhill, the scientists were able to computerize the entire measurement process, using a soundcard fed through a 1000 watt amplifier and the responses captured "using the swept sine measurement method, with a length of 10 seconds... (exciting) the site at every frequency between 20Hz and 20kHz."

Although the original is stone, including the famous Welsh bluestone, and Maryhill is made of concrete, the audio difference from the two surfaces is negligible, in Fazenda's opinion. Probably in part due to the Maryhill designers' decision to texturize the concrete surfaces. Due to the regularity of the Maryhill structure it has more high-end diffusion than Stonehenge, though they are very close on the low end.

The study's conclusion is that Stonehenge was a reflective environment, in which any sound is made to reverberate due to the flat, hard surfaces.

"The existence of a 1 second Reverberation Time would certainly be noticeable to any person entering the circle. Interestingly, 1s is a typical, optimal RT for a large lecture hall, ensuring good speech intelligibility. Anecdotally, the space exhibited this feature, i.e. speech was clearly audible regardless of speaker and listener position, undoubtedly due to the large number of reflective surfaces surrounding them but also due to the high degree of scattering provided by the interspacing between the stones, preventing any strong reflections from becoming a nuisance when interacting with the direct sound from the speaker."

Scientists, whether acoustic scientists or archaeologists, are for good reason reticent to draw conclusions that are not based on provable, duplicable facts. But at least we can do this. Picture what such a structure, with such an acoustical profile, would have meant experientially to visitors. Quite aside from any overt religious message, cult activity, and astronomical import, anyone entering the site would have felt the sense of sound change. Sound echoed, but in a specific way, bouncing from the stones' surfaces, but being rescued from noise by the interstices between them.

Proclamations must have borrowed a sense of supernatural import, prayers a kind of aural fecundity they would have been denied outside the circle. The human imagination values form. The circular form of Stonehenge, and the relationship of points therein, must have been lent an otherworldly dynamic by the special character of its sound.

25 Reader Comments

interesting article. Does anyone know WHY you cant have electricity at stonehedge? will it open a vortex to another dimension or something? Are we keeping cthulhu out by not letting electricity near it?

There's no electricity allowed, so you have to use batteries instead. Apparently the batteries put out, um, must be sound energy or something instead of the electricity that you get from "conventional" batteries. :-)

As a skeptic, I was impressed with and certainly able to understand the seemingly supernatural nature of the chambers in the temples at Machu Picchu. You stick your head in a trapezoidal hole bounded on 5 sides, hum the right frequency, and due to the precisely designed structure the sound amplifies, reverberates, and seems to be originating from and be received by the very center of your head. It sort of rolls into itself and makes your head feel like its expanding literally. So I'm sure it provided the priests with a great metaphor for one's mind expanding. It's hard to describe really, it provided a sensation so unlike anything else I've encountered outside of recreational drug use in college. I've heard a somewhat similar effect at lower frequencies in a toilet stall but none so perfectly tuned as these head sized chambers. Obviously the toilet is less likely to inspire religious thoughts. It's interesting to see Stonehenge had particular acoustic qualities. While the echo chambers at Machu Picchu seemed designed solely for this purpose I also wonder if Stonehenge merely has these properties due to its configuration or if it was planned that way.

Though it doesn't address this particular study, please read Alun Salt's comments about acoustic studies at Stonehenge (http://alunsalt.com/2012/02/25/if-your- ... not-yours/). It contains some very important caveats that should be taken into account before accepting the findings too readily.

Proclamations must have borrowed a sense of supernatural import, prayers a kind of aural fecundity they would have been denied outside the circle. The human imagination values form. The circular form of Stonehenge, and the relationship of points therein, must have been lent an otherworldly dynamic by the special character of its sound.

WTF? When did Ars turn into a site for mystical mumbo-jumbo?

Stonehenge has a RT similar to lecture halls, and I doubt that most of us sense any "supernatural import" or "awe" from the "proclamations" (note: these are usually called speeches or talks by the less verbose amongst us) made in them.

Proclamations must have borrowed a sense of supernatural import, prayers a kind of aural fecundity they would have been denied outside the circle. The human imagination values form. The circular form of Stonehenge, and the relationship of points therein, must have been lent an otherworldly dynamic by the special character of its sound.

WTF? When did Ars turn into a site for mystical mumbo-jumbo?

Stonehenge has a RT similar to lecture halls, and I doubt that most of us sense any "supernatural import" or "awe" from the "proclamations" (note: these are usually called speeches or talks by the less verbose amongst us) made in them.

Nothing mumbo-jumbo about this; quite the opposite in fact. This provides a rational explanation for a subjective spiritual experience. The experience of spirituality is widely accepted by science, it is the supernatural origin of that experience that rational observers call into question.

I love Stonehenge! But i guess its natural because im welsh heheh! And so proud of it! I love Wales! I wanted to add this also! Quite awhile back i had read a book about the How Rocks can record sounds of things and people around them! They called it the Stone Tapes! Of course i laughed when i read it but stop and think! We now have delicate accoustical instruments that may be able to pick up these sounds recorded in the stones!Folks im serious, we may well be hearing the actual music of 5,000 years ago! In the Bible there is a verse that says if every voice were stilled even the very rocks and stones would shout aloud! Maybe it was trying to tell us something after all! Listen to what the Stones are saying people!

I love Stonehenge! But i guess its natural because im welsh heheh! And so proud of it! I love Wales! I wanted to add this also! Quite awhile back i had read a book about the How Rocks can record sounds of things and people around them! They called it the Stone Tapes! Of course i laughed when i read it but stop and think! We now have delicate accoustical instruments that may be able to pick up these sounds recorded in the stones!Folks im serious, we may well be hearing the actual music of 5,000 years ago! In the Bible there is a verse that says if every voice were stilled even the very rocks and stones would shout aloud! Maybe it was trying to tell us something after all! Listen to what the Stones are saying people!

Curt Hopkins / Curt writes for Ars Technica about the intersection of culture and technology, including the democratization of information, spaceships, robots, the theatre, archaeology, achives and free speech.